Brecht Van Lommel did a wonderful job on OSL integration in Cycles, as he did a wonderful job for Solid Angle Arnold.

For now 6 years, we use Blender for easy OSL dev., using included script editor, realtime render update, etc...
And, most impressive, Blender is still ahead! It includes closures and other advanced OSL functions not yet available in 3DSMax.

I started teaching OSL using Blender in 2013. Students were wondering why... Now, they are immediately proficient in writing OSL Shaders in 3DS Max 2019, from the first day!
Now, they can use their knowledge in the biggest and most powerful renderers !